/v2/wvw/matches: add more objective fields.

[lye]

• points_capture/points_tick since points are variable now.
• upgrades containing a list of slotted upgrades.

I'm not altogether happy with the output format, very open to suggestions.

Fixes #181; doesn't yet expose yaks needed for next tier.
Fixes #394.
Refs #118. Localized upgrade stuff (and the yaks/tier) needs to be added somewhere.

[thetoothpick]

It'd be nice if you could expose the objective upgrade level (i.e. tier) in the "upgrades" key instead of guild upgrades, and move those to "guild_upgrades". You can calculate the level based on the number of yaks delivered, but those numbers aren't published in the API anywhere from what I can tell, and hardcoding them would be awkward.

Besides, guild upgrades are a separate concept from objective upgrades, and should be put in a separate key so people don't confuse them.

[lye]

I think the yaks/upgrade bits need to go into /v2/wvw/objectives since there's some additional localized info for them (icons, names, etc) -- split out into #422.

[lye]

Uhh, this went out a bit early and I kind of botched it (didn't get the upgrades -> guild_upgrades change).

I should do that real quick.